Occupational Dose Evaluation in Support of the Development of
October, 2012
Rare Element Resources, Inc. Bear Lodge Project
10
A Hydromet plant for recovery of REE’s from the pre-concentrate to form an RE
carbonate concentrate product in Upton, Wyoming.
The proposed process flow for the PUG and Hydromet is shown in Figure 2.1
2.1
Bull Hill Mine
The BHM is intended to be a typical truck and shovel open pit mining operation that will extract
near-surface ore reserves of REE’s. Currently, the expected life of the mine is 19 years (y). The
maximum mining rate to meet expected ore production is 28,000 tons per day (RER, 2012). This
mining rate is required for initial start-up and includes pre-stripping of any overburden material.
The mining rate will decrease in the first year of ore production and over the mine life. The
mining schedule is designed to produce 1,000 tons per day of high grade oxide or oxide-
carbonate (OXCA) ore. A more detailed description of the mine design and production schedule
can be found in
Technical Report on the Mineral Reserves and Development of the Bull Hill
Mine
(RER, 2012).
2.2
Physical Upgrade Plant
The PUG process uses an iterative series of crushing, attrition, washing and screening methods to
concentrate the REE fines and reduce the overall physical mass of material to be further
processed. The PUG is designed to process 1000 tons per day of high grade oxide or 1000 tons
per day of OXCA and stockwork ores. These product streams combined will produce 188 tons
per day of REE pre-concentrate that will be transported via truck to the Hydromet plant. The pre-
concentrate will have REE content of 14 percent with a moisture content of 10 percent on a
weight basis (RER, 2012).
Flocculent will be used to increase the separation efficiency of solid particles from the water.
The process will require an estimated 72 pounds per day of flocculent, which may change
depending on the production rate.
Engineering controls will mitigate dust emissions from the process. Much of the PUG process
will be wet and enclosed. In addition, and as shown in Figure 2.1, dust collectors will be used --
prior to ventilation-- on the drying end of the process.
